title: Isothermal titration calorimetry of Ni(II) binding to histidine and to N-2-aminoethylglycine.
abstract: Isothermal titration calorimetry (ITC) is used to study the complexation thermodynamics of Ni(II) with histidine (His) and with N-2-aminoethylglycine (EDMA). The titrations were performed in HEPES and Tris buffers at various ionic strengths and pH values around 8. The results show the influence of the experimental conditions on the shape and fitting parameters of the calorimetric curves. For the studied systems, the main reaction is concomitant with a number of side reactions which contribute to the global energy measured. From the calorimetric data measured, the formation constants for the species NiHEPES(+), Tris(+)His(-), TrisNiHis(+) and [Ni(EDMA)(2)OH](-) have been evaluated for the first time and the values obtained properly validated.
authors.affiliation: Departament de Química Analítica and Institut de Biomedicina (IBUB), Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain.
authors.forename: Gemma
authors.initials: G
authors.lastname: Garrido
authors.forename: Clara
authors.initials: C
authors.lastname: Ràfols
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Bosch
mesh_terms: D002151:Calorimetry / Q000379:methods*; D005998:Glycine / Q000031:analogs & derivatives* / Q000737:chemistry; D006639:Histidine / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009532:Nickel / Q000737:chemistry*; D009994:Osmolar Concentration
chemical_list: C028791:N-(2-aminoethyl)glycine; D006639:Histidine; D009532:Nickel; D005998:Glycine